Dröge M, Pühler A, Selbitschka W
University of Bielefeld, Department of Genetics, Germany.
J Biotechnol. 1998 Sep 17;64(1):75-90. doi: 10.1016/s0168-1656(98)00105-9.
The transfer of genetic information between distantly or even unrelated organisms during evolution had been inferred from nucleotide sequence comparisons. These studies provided circumstantial evidence that in rare cases genes had been laterally transmitted amongst organisms of the domains bacteria, archaea and eukarya. Laboratory-based studies confirmed that the gene pools of the various domains of organisms are linked. Amongst the bacterial gene exchange mechanisms transduction, transformation and conjugation, the latter was identified as the mechanism with potentially the broadest host range of transfer. Previously, the issue of horizontal gene transfer has become important in the context of biosafety. Gene transfer studies carried out under more natural conditions such as in model ecosystems or in the environment established that all gene transfer mechanisms worked under these conditions. Moreover, environmental hot-spots were identified where favourable conditions such as nutrient enrichment increased the probability of genetic exchange among bacteria. In particular, the phytosphere was shown to provide conducive conditions for conjugative gene exchange. Concern has been expressed that transfer of recombinant DNA (e.g. antibiotic resistance genes) from genetically modified organisms (GMOs) such as transgenic plants to phytosphere bacteria may occur and thus contribute to the undesirable spread of antibiotic resistance determinants. Studies which were performed to address this issue clearly showed that such a transfer occurs, if at all, at extremely low frequency.
在进化过程中，远距离甚至不相关的生物体之间遗传信息的转移已通过核苷酸序列比较推断出来。这些研究提供了间接证据，表明在极少数情况下，基因在细菌、古菌和真核生物域的生物体之间横向传递。基于实验室的研究证实，生物体各个域的基因库是相互关联的。在细菌基因交换机制转导、转化和接合中，后者被确定为可能具有最广泛宿主转移范围的机制。此前，水平基因转移问题在生物安全背景下变得重要起来。在更自然的条件下，如在模型生态系统或环境中进行的基因转移研究表明，所有基因转移机制在这些条件下都起作用。此外，还确定了环境热点地区，在这些地区，诸如营养富集等有利条件增加了细菌之间基因交换的可能性。特别是，植物圈被证明为接合基因交换提供了有利条件。有人担心，重组DNA（如抗生素抗性基因）从转基因植物等转基因生物转移到植物圈细菌可能会发生，从而导致抗生素抗性决定因素的不良传播。为解决这一问题而进行的研究清楚地表明，这种转移即使发生，频率也极低。
